Jet pump



A. Y. DODGE May 26, 1964 JET PUMP Filed Aug. 7, 1961 2 Sheets-Sheet 1 [zUezzfon \Doa' e, %m

Q/ g z'el W 2 Sheets-Sheet 2 A. Y. DODGE JET PUMP May 26, 1964 Filed Aug. '7, 1961 United States Patent 3,134,338 JET PUMP Adiel Y. Dodge, A. Y. Dodge 00., 206 S. Main 'St., Rockford, Ill. Filed Aug. 7, 1961, Ser. No. 129,689 8 Claims. (Cl. 103-262) This invention relates to jet pumps and more particularly to an ejector pump for moving large volumes of fluid at low pressure.

In various processes involving evaporating of liquid at low presure, such as in evaporative cooling, concentrating or drying solutions or distillation processes, it is necessary to pump very large volumes of vapor at extremely low pressure, often on the order of l or 2 p.s.i.a. Conventional mechanical pumps are not at all suited for this purpose and while jet pumps or ejectors have desirable characteristics for the purpose, their efficiency as they have heretofore been constructed is very low. For example, in a conventional effector the nozzle for converting static pressure to velocity may function at about 97% efficiency, the suction chamber may function at about 50% efficiency and the diffuser at about 80% efficiency giving an overall efficiency of about 39%.

There are various reasons for this low efficiency, including turbulence, short-circuiting of fluid flows, particu- ..larly in the diffuser chamber, shock and the like. Thus,

when the propellent fluid contacts the fluid to be aspirated and which is at lower pressure and traveling at a much lower velocity, eddy currents and similar turbulences are set up. As the fluid travels into and through the diffuser chamber wherein flow is reconverted to pressure, additional turbulence occurs and there is a tendency of the fluid to short-circuit into the low pressure area of the jet.

These various factors result in an extremely inefficient operation.

It is accordingly one of the objects of the present in- I vention to provide a jet pump in which fluid is caused to flow smoothly through the pump with a minimum of turbulence.

Another object is to provide a jet pump in which shortcircuiting of the fluid is prevented.

According to a feature of the invention, angular vanes are provided in the pump which cause the fluid to swirl as it flows through the pump. Swirling of the fluid in the coaxial passages carrying the propellant fluid and the fluid to be aspirated enables contact to be madebetween the different fluids with a minimum of shock and turbulence. Swirling of the fluid in the diffuser chamber 'creates a smooth flow condition and tends to eliminate short-circuiting. In addition, the swirling creates a centrifugal force which increases the vacuum in the passage carrying the fluid to be aspirated thereby to increase the pressure head across the pump and to increase its efficiency. I

A further object is to provide a jet pump in which fluid is fed into a vortex chamber from the diffuser chamber and from it it is discharged tangentially in a smooth description when read in connection with the accompanying drawings, in which:

FIGURE 1 is a sectional view with parts in elevation through a jet pump embodying the invention; 1

FIGURE 2 is a view similar to FIGURE 1 of an alter: I native construction;

- bodying the invention.

FIGURE 3 is an end elevation of the pump of FIG- URE 2 with parts broken away;

FIGURES 4 and 5 are views corresponding to FIG- URES 2 and 3 respectively of another alternative pump construction;

FIGURE 6 is a section on the line 6-6 of FIGURE 4;

FIGURES 7 and 8 are views corresponding to FIG- URES 2 and 3 respectively of still another form of pump embodying the invention;

FIGURE 9 is a sectional view with parts in elevation of still another form of jet pump embodying the invention;

FIGURE 10 is a sectional view with parts in elevation of still another form of jet pump embodying the invention; and

FIGURE 11 is a diagrammatic view with parts in section of an evaporating system employing a jet pump em- The aparatus as shown that disclosed in my co pending application Serial No. 100,212, filed April 3, 1961, now matured into Patent No. 3,007,322. As shown, it comprises an outer tubular conduit 41 tapering from its inlet end to its discharge end and having a tangential inlet connection 42 at its larger inlet end. A coaxial tapered conduit 43 is mounted within the conduit. 41 and spaced from the walls thereof to define therewith coaxial passages. As shown the passage through the inner conduit 43 tapers to a point spaced slightly from its discharge end and then flares outwardly to its discharge end. Fluid is supplied to the conduit 43 through an inlet connection 44 at the large end thereof.

The outer conduit 41 terminates in an outwardly flaring portion 45 beyond the end of the conduit 43 having a tached to the flange 46 and forms a continuation of the flaring portion 45 to define a diffuser chamber increasing in area in which the velocity components of the fluid are reconverted to pressure.

According to the present invention the fluid flowing through the jet pump is caused to swirl. The tangential inlet 42 contributes to this-and swirling is further produced by a twisted or angular vane 47 in the inner conduit 43 and a similar angular or twisted vane 48 in the annular passage between the conduits 41 and 43. Both vanes are pitched in the same direction so that the fluids flowing through both passages will be caused to swirl in the same direction, this swirling continuing through the diffuser chamber.

Swirling of the fluid in the jet pump passages accomplishes several advantageous purposes. Since the propellent fluid, which is preferably supplied through the inlet opening 42 and flows through the outer passage, is swirling in the same direction as the fluid to be aspirated, which normally enters through the inlet 44 and travels through the inner conduit 43, the two fluids can blend smoothly in the area adjacent to the outlet of the conduit 43 in a laminar manner to minimize or eliminate turbulent mixing. Also, the swirling of the fluids tends to create a low pressure area at the outlet of the inner conduit 43 due to centrifugal force thereby increasing the degree of vacuum present at this area and functioning more efficiently to aspirate the fluid through the inner conduit.

Furthermore, as the swirling flow continues through the diffuser chamber 45 and 47, it tends to prevent fluid from short-circuiting back to the low pressure area centrally of the inner conduit 43 and near the entranceto the diffuser chamber. The swirling flow in the diffuser chamber tends to maintain its laminar characteristics so that eddy currents and turbulence which normally occur in comparable diffuser chambers are minimized or eliminated.

It has been found that with a construction, as shown, the nozzle defined by the outer passage for converting in FIGURE 1 corresponds to numerals.

static pressure to velocity can function with an efliciency of about 95%, the suction chamber or inner passage in the conduit 43 can function with an efliciency of about 93% and the diffuser can function with an efliciency of about 94% giving an overall efficiency of about 83%. It will be observed that this constitutes a substantial improvement over conventional jet pumps.

FIGURES 2 and 3 illustrate an alternative construction in which parts identical to corresponding parts in FIG- URES 1 and 2 have been indicated by the same reference In this construction the diffuser chamber 47 is replaced by a flaring diffuser chamber 55 having a flange 56 at its inlet end to be connected to the flange 46. An annular series of vanes 57 are mounted between the flanges 46 and 56 adjacent to the inlet of the diffuser chamber to augment the swirling action of the fluid as it enters the diffuser chamber. Preferably a hub member 54 is centrally supported by the vanes 57 so that the vanes 57 define an annular passage for the fluid around the hub member. The hub member 54 may be streamlined, as shown, to present minimum interference with flow of fluid.

At its outlet end, the diffuser chamber has connected thereto a vortex chamber 59 which is preferably spiral in cross section, in the manner of a conventional snail shell blower chamber. A tangential outlet 58 is provided at the maximum cross section portion of the chamber 59 opening in the direction counter to that in which the fluid is swirling so that the fluid will flow smoothly through the vortex chamber and out the outlet opening. Preferably, an annular series of guide vanes 60 are provided between the outlet of the diffuser chamber and the vortex chamber.

In this construction, the vanes 60 further augment the swirling action of the fluid as it flows from the difluser chamber into the vortex chamber and the vortex chamber smoothly picks up the swirling fluid and directs it through the tangential outlet 58. Thus the velocity of the fluid is smoothly and efliciently converted back to static pressure without any turbulence or other efliciency losses.

FIGURES 4, 5 and 6 illustrate a further alternative construction, parts therein corresponding to like parts in FIGURES 2 and 3 being indicated by the same reference numerals, plus 400. In this construction the inner and outer conduits 441 and 443 are of uniform diameter with the inner conduit 443 tapering to a closed end within the conduit 441. Swirling fluid within the inner conduit 443 is discharged therefrom through tangential openings or louvers 426 in the walls thereof and within the outer conduit 441. These louvers, as indicated, may be distributed over an appreciable portion of the length of the conduit 443 so that the fluid to be aspirated will flow through the louvers and will mix smoothly with the propellant fluid flowing through the annular passage between the two conduits.

In this case also the diffuser chamber 455 is defined by an integral continuation of the conduit 441 and the vanes 57 are omitted. Otherwise, this construction is substantially similar to that of FIGURES 2 and 3 and functions in the same manner.

FIGURES 7 and 8 illustrate still another alternative construction, parts therein corresponding to like parts in FIGURES 2 and 3 being indicated by the same reference numerals, plus 700. In this configuration, the diffuser chamber 755 is defined by an integral continuation of the outer conduit 741. The inner conduit 743 is formed with a bulbous discharge end 772 and vanes 773 are provided in the annular space between the bulbous end and the outer conduit 741 to augment the swirling action of the fluid.

A core member 771 is supported by the set of vanes 760 and tapers toward the end of the conduit 743 with its extreme end projecting into the bulbous end 772 of this conduit. A helical vane 774 is mounted in the space between the core member 771 and the wall of the diffuser 4 chamber 775 to augment and continue the swirling of the fluid.

In this construction, the bulbous end 772 defines with the wall of the outer conduit a venturi shaped passage which sets up a zone of high velocity adjacent to the point of discharge fluid from the inner conduit 743. This tends to increase the suction or aspirating effect and coupled with the centrifugal effect produced by the swirl ing action adds to the efficiency of the jet pump. The core 771, together with the vane 774 thereon not only augments the swirling action, but positively prevents any short-circuiting of the fluid so that a highly etficient operation results.

In the embodiment of the invention shown in FIGURE 9, parts corresponding to like parts in FIGURES 2 and 3 are indicated by the same reference numerals, plus 900. In this construction, the propellant fluid enters through the passage 942 in the conduit 941 which is given a reverse flared configuration, as shown. The inner conduit 943 is given a corresponding reverse flared configuration and, in addition, is provided with an inner high velocity nozzle 977 communicating with the inlet passage 942 to receive the high pressure propellant fluid. The passages are provided with angular vanes 947 and 948, as in the previous constructions, to give a swirling action as the fluid flows through the passages.

The diffuser chamber 955 is formed as a flaring continuation of the outer conduit 941 and joins a vortex chamber 959 with an annular series of vanes 960 therebetween, as in FIGURES 2 and 3. In this case, a core member 971 is secured in the vortex chamber and projects therefrom toward the end of the inner conduit 943 where it tapers downwardly, as shown at 978, to terminate in a relatively sharp point 979 centrally of the discharge end of the inner conduit. Vanes 930 are secured to the core member 978 to augment the swirling action of the fluid as it flows through the diffuser chamber and also to prevent any short-circuiting of the fluid in the diffuser chamber.

In this construction, due to the shape of the conduits 941 and 943, the vanes 947 and'948 are located in expanding areas of the coaxial passages rather than in contracting areas, as in FIGURES 1 and 2. This shaping of the passages combined with the swirling action of the fluid tends to reduce the pressure at the discharge end of the inner conduit 943 and to increase the efliciency of the action. The provision of the inner nozzle 977 tends further to aspirate fluid through the inner conduit 943 to increase the volume of fluid so aspirated thereby further increasing the efficiency of operation.

The jet pump shown in FIGURE 10 is generally similar to that of FIGURE 9 with various modifications and parts therein corresponding to like parts in FIGURES 2 and 3 are indicated by the same reference numerals, plus 1000. In this construction, both the inner and outer conduits flare from substantially their inlet ends to their outlet ends. However, the rate of flare of the inner conduit is greater than that of the outer conduit so that the annular flow passage between them decreases in area from the inlet to the outlet end. A tapered core member 1071 extends from the inlet of the diffuser chamber well into the flared discharge end of the inner conduit 1043 and carries one or more angular vanes 1080 extending substantially throughout the length thereof. The flare of this core member is somewhat greater than that of the inner conduit so that the annular flow passage defined between them and within which the vanes 1080 partially lie decreases in flow area toward the discharge end.

With these constructions, due to the flaring passages and decreasing flow area thereof, maximum efliciency of the vortex flow is achieved and the fluid is caused to flow smoothly from the inlet ends of the passages through the diffuser chamber and vortex chamber to the outlet opening. It has been found that with these constructions comparable efiiciencies are achieved whether the high pressure propellent fluid is supplied through the inner or outer passage and this is true to a large degree of the constructions shown in FIGURES 1, 2, 7, 8 and 9. It is preferred, however, to supply high pressure, high velocity propellent fluid through the outer passages in all cases.

FIGURE 11 illustrates an evaporative system employing a jet pump according to the invention and further shows a somewhat modified form of jet pump. In this system, as shown, material to be vaporized is contained in a chamber indicated at 10. Large volumes of Vapor at low pressures on the order of 1 or 2 psi. are to be pumped from the container and recondensed either for cooling purposes, for distillation or for drying or concentrating solutions.

A pump 11 is provided which is illustrated as a rotary vane pump having an inlet conduit 12 connected to the container and an outlet conduit 13 connected to the inner nozzle 14 of an ejector or jet pump. The pump 11 will take fluid or vapor from the container 10, compress it and supply it to the nozzle 14 which acts to aspirate a larger volume of fluid from the container through an outer conduit 15. To supplement the flow of fluid and to increase the inlet pressure on the pump, a conduit 16 may be provided connected to the pump discharge conduit 13 and supplying nozzles 17 and 18 which cooperate with inlet ends of the conduits 12 and to form small jet pumps tending to pump vapor from the container into these conduits. In order to dampen out pulsations in the pump discharge pressure, an air bell 19 may be connected to the conduit 13 adjacent to the pump nozzle 14, as shown.

Beyond the nozzle 14, the outer conduit 15 narrows down to a venturi throat 21 and then flares outwardly. A diffuser chamber 22 may be connected to the discharge end of the venturi section 22 and may have heat radiating vanes 23 thereon to assist in condensing the vapor. Additionally, cooling tubes 24 may extend through the diffuser chamber adjacent to its discharge end to condense the vapor.

In order to cause the fluid to swirl as it enters and flows through the diffuser chamber, a core member 25 is mounted in the inlet end of the diffuser chamber and is spaced from the walls thereof to define an annular flow passage. Angular vanes 26 are carried by the core member and lie in the annular passage to cause the fluid to swirl as it enters and flows through the diffuser chamber with the effect and for the purposes as described above in connection with the other embodiments.

In this construction, vapor at low pressure will be withdrawn from the container 10 by the pump 11 which will discharge the vapor at increased pressure through the nozzle 14. The aspirating effect of the nozzles 17 and 18 will cause a larger volume of vapor at low pressure to be drawn through the conduit 15. As the vapor passes over the vanes 26 into the diffuser chamber it will be caused to swirl and will continue to swirl through the difluser chamber so that the velocity thereof will be converted smoothly and efficiently back to static pressure. Cooling of the fluid due to contact with the diffuser chamber walls and with the condenser tubes 24 will condense the vapor and the condensate may be drawn off in any desired manner.

The jet pump of the invention may be used for a multitude of different purposes whenever it is desired to pump a large volume of fluid with a relatively high degree of efliciency by means of a second fluid. In addition to the examples given above, the pump would find a high degree of utility in connection with the air cooling of internal combustion engines where the exhaust might be utilized as the propellent fluid to aspirate air over the engine to cool it. Various other applications in which a large volume of fluid is to be moved and particularly at relatively low pressure will be apparent.

While several embodiments of the invention have been shown and described herein, it will be understood that they are illustrative only and not to be taken as a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

1. A jet pump comprising coaxial conduits defining coaxial passages, one of the passages receiving a propellent fluid under relatively high pressure and the other being connected to a source of fluid to be aspirated, means defining a diffuser chamber connected to and forming a continuation of the outer conduit to receive fluid flowing it smoothly from the vortex chamber.

2. The jet pump of claim 1 including a central core at the inlet end of the diffuser chamber defining an annular passage in which the first vanes are positioned.

3. A jet pump comprising coaxial conduits defining coaxial passages, one of the passages receiving a propellent fluid under relatively high pressure and the other being connected to a source fluid to be aspirated, angular sets of vanes in the passages to cause fluid flowing therethrough to swirl in the same direction, means defining a diffuser chamber connected to the outer conduit and flaring smoothly outward therefrom, a core positioned centrally in the diffuser chamber and spaced from the inner surface thereof to define therewith an annular passage, and angular vanes in the annular passage to cause the fluid flowing therethrough to continue to swirl in the same direction.

4. The jet pump of claim 3 in which the core extends into the discharge end of the inner conduit.

5. A jet pump comprising coaxial conduits defining coaxial passages, one of the passages receiving a propellent fluid under relatively high pressure and the other being connected to a source of fluid to be aspirated, angular sets of vanes in the passages to cause fluid flowing therethrough to swirl in the same direction, means defining a diffuser chamber connected to the outer conduit and flaring smoothly outward therefrom, a core positioned centrally in the diffuser chamber and spaced from the inner surface thereof to define therewith an annular passage, angular vanes in the annular passage to cause the fluid flowing therethrough to continue to swirl in the same direction, means defining a vortex chamber connected to the diffuser chamber to receive swirling fluid therefrom, and means defining a tangential outlet from the vortex chamber facing toward the swirling fluid therein to conduct it smoothly from the vortex chamber.

6. A jet pump comprising coaxial conduits defining coaxial passages, one of the passages receiving a propellent fluid under relatively high pressure and the other being connected to a source of fluid to be aspirated, angular sets of vanes in the passages to cause fluid flowing therethrough to swirl in the same direction, means defining a diffuser chamber connected to the outer conduit and flaring smoothly outward therefrom, a core positioned centrally in the diffuser chamber and spaced from the inner surface thereof to define therewith an annular passage, angular vanes in the annular passage to cause the fluid flowing therethrough to continue to swirl in the same direction, means defining a vortex chamber connected to the diffuser chamber to receive swirling fluid therefrom, means defining a tangential outlet from the vortex chamber facing toward the swirling fluid therein to conduct it smoothly from the vortex chamber, and a set of angular vanes between the diffuser chamber and the vortex chamber to cause the fluid to continue to swirl in the same direction.

7. A jet pump comprising coaxial conduits defining cod axial passages, means to supply a propellent fluid under relatively high pressure to the outer passage, means to connect the inner passage to a source of fluid to be aspirated, angular sets of vanes in both of the passages to cause fluid flowing therethrough to swirl in the same direction in a vortex swirl creating a low pressure core at the center of the vortex and causing a higher pressure region at the periphery of the vortex, means defining a diffuser chamber connected to the outer conduit and increasing in area smoothly outward therefrom, and angufluid under relatively high pressure and the other being 1 connected to a source fluid to be aspirated, angular sets of vanes in the passages to cause the fluid flowing therethrough to swirl in the same direction, means defining a diffuser chamber connected to the outer conduit and flaring smoothly outward therefrom, a core positioned cen- 8 trally in the diffuser chamber and spaced from the inner surface thereof to define therewith an annular passage, the core extending into the discharge end of the inner conduit, angular vanes in the annular passage to cause the fluid flowing therethrough to continue to swirl in the same direction, the conduits flaring toward the diffuser chamber and cooperating with each other and with the core to define annular passages which increase in radius and decrease in cross sectional area toward the diffuser 10 chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,303,210 Klein May 6, 1919 1,622,155 Kobiolke Mar. 22, 1927 1,739,600 Loth Dec. 17, 1929 FOREIGN PATENTS 494,225 France May 24, 1919 

1. A JET PUMP COMPRISING COAXIAL CONDUITS DEFINING COAXIAL PASSAGES, ONE OF THE PASSAGES RECEIVING A PROPELLENT FLUID UNDER RELATIVELY HIGH PRESSURE AND THE OTHER BEING CONNECTED TO A SOURCE OF FLUID TO BE ASPIRATED, MEANS DEFINING A DIFFUSER CHAMBER CONNECTED TO AND FORMING A CONTINUATION OF THE OUTER CONDUIT TO RECEIVE FLUID FLOWING THROUGH BOTH OF THE PASSAGES, MEANS DEFINING A VORTEX CHAMBER CONNECTED TO AND RECEIVING FLUID FROM THE DIFFUSER CHAMBER, MEANS DEFINING A TANGENTIAL OUTLET FROM THE VORTEX CHAMBER, FIRST ANGULAR VANES UPSTREAM OF THE DIFFUSER CHAMBER TO CAUSE THE FLUID TO SWIRL AS IT FLOWS THROUGH THE DIFFUSER CHAMBER, AND SECOND ANGULAR VANES BETWEEN THE DIFFUSER AND VORTEX CHAMBERS TO CAUSE THE FLUID TO CONTINUE TO SWIRL IN THE SAME DIRECTION, THE TANGENTIAL OUTLET FACING TOWARD THE SWIRLING FLUID TO CONDUCT IT SMOOTHLY FROM THE VORTEX CHAMBER. 